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Peculiar Bi-ion dynamics in Na1/2Bi1/2TiO3from terahertz and microwave dielectric spectroscopy

Petzelt, Jan and Nuzhnyy, Dmitry and Bovtun, Viktor and Paściak, Marek and Kamba, Stanislav and Dittmer, Robert and Svirskas, Šarunas and Banys, Juras and Rödel, Jürgen (2014):
Peculiar Bi-ion dynamics in Na1/2Bi1/2TiO3from terahertz and microwave dielectric spectroscopy.
In: Phase Transitions, pp. 953-965, 87, (10-11), ISSN 0141-1594,
[Online-Edition: http://dx.doi.org/10.1080/01411594.2014.953517],
[Article]

Abstract

Dynamics of the main dielectric anomaly in Na1/2Bi1/2TiO3 (NBT) were studied by time-domain THz and microwave spectroscopy, using also previously published data and their new overall fits. Above the dielectric maximum temperature Tm ≈ 600 K, the response consists of coupled sub-THz oscillator and a relaxation mode, assigned to strongly anharmonic Bi-ion vibrations and hopping, whose slowing down explains the paraelectric-like permittivity increase to Tm. Below Tm, the main relaxation continues slowing down and additional relaxation, assigned to quasi-Debye losses, appears in the 1011 Hz range. The oscillator hardens on cooling and takes over the whole oscillator strength. The permittivity decrease below Tm is caused by the reduced strength of the relaxations due to dominance of the rhombohedral phase within the coexistence region with the tetragonal phase. The anharmonic dynamics of Bi are supported by previous structural studies. NBT represents a hybrid between standard and relaxor ferroelectric behaviour.

Item Type: Article
Erschienen: 2014
Creators: Petzelt, Jan and Nuzhnyy, Dmitry and Bovtun, Viktor and Paściak, Marek and Kamba, Stanislav and Dittmer, Robert and Svirskas, Šarunas and Banys, Juras and Rödel, Jürgen
Title: Peculiar Bi-ion dynamics in Na1/2Bi1/2TiO3from terahertz and microwave dielectric spectroscopy
Language: English
Abstract:

Dynamics of the main dielectric anomaly in Na1/2Bi1/2TiO3 (NBT) were studied by time-domain THz and microwave spectroscopy, using also previously published data and their new overall fits. Above the dielectric maximum temperature Tm ≈ 600 K, the response consists of coupled sub-THz oscillator and a relaxation mode, assigned to strongly anharmonic Bi-ion vibrations and hopping, whose slowing down explains the paraelectric-like permittivity increase to Tm. Below Tm, the main relaxation continues slowing down and additional relaxation, assigned to quasi-Debye losses, appears in the 1011 Hz range. The oscillator hardens on cooling and takes over the whole oscillator strength. The permittivity decrease below Tm is caused by the reduced strength of the relaxations due to dominance of the rhombohedral phase within the coexistence region with the tetragonal phase. The anharmonic dynamics of Bi are supported by previous structural studies. NBT represents a hybrid between standard and relaxor ferroelectric behaviour.

Journal or Publication Title: Phase Transitions
Volume: 87
Number: 10-11
Uncontrolled Keywords: sodium bismuth titanate, terahertz spectroscopy, broadband dielectric spectroscopy, phase-transition dynamics, Bi-ion dynamics
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis > Subproject A1: Manufacturing of ceramic, textured actuators with high strain
11 Department of Materials and Earth Sciences > Material Science
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
11 Department of Materials and Earth Sciences
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 12 Dec 2014 08:48
Official URL: http://dx.doi.org/10.1080/01411594.2014.953517
Additional Information:

SFB 595 A1

Identification Number: doi:10.1080/01411594.2014.953517
Funders: The research was supported by the Czech Science Foundation (project 13-15110S). R. Dittmer acknowledges support from the German Research Foundation DFG within the collaborative research centre SFB595.
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